Abstract: A refurbished rotor of a wound rotor machine. The refurbished rotor includes a plurality of windings assembled to the rotor core, each manufactured from two separate bars: a top coil and a bottom coil. The top coil is positioned in a rotor core slot at a position radially outward of a position of the bottom coil within another rotor core slot. Each top coil and each bottom coil has a flat rectangular cross-section. On a connection end of the rotor where rotor leads are attached, the top coil has a flat end positioned alongside and in alignment with a flat end of the bottom coil of an adjacent one of the plurality of windings. The top coil and the bottom coil have respective flat ends joined to each other on a non-connection end of the rotor opposite the connection end by a joint for establishing electrical continuity.

Abstract: An insulation system of a current-carrying conductor of an electric machine. The insulation system comprises a thermally curable resin including a polymer resin matrix and a nanoparticulate filler. A mica paper or mica tape is impregnated with the thermally curable resin. The thermally curable resin comprises nanoparticulate filler, the total quantity of nanoparticulate filler being at least 0.1 wt % and not more than 0.5 wt %.

Abstract: Transposition coils and insulation for transposition coils. One example provides a transposition coil including a plurality of conductor turns arranged in at least two separate stacks and an outer main wall insulation that encircles the at least two separate stacks. Each of the at least two separate stacks are provided with dedicated main wall insulation that encircles exactly one of the at least two separate stacks.

Abstract: Transposition coils and insulation for transposition coils. One example provides a method including providing a first conductor and a second conductor in at least two separate stacks, the first conductor extending along a first axis and the second conductor extending along a second axis, forming a double stack, forming a bridge connection between the at least two separate stacks, providing each of the two separate stacks with a dedicated main wall insulation that encircles exactly one of the at least two separate stacks, and providing an outer main wall insulation that encircles the at least two separate stacks.

Abstract: An insulation system for an electric machine coil includes the following layers situated in sequence over an insulated conductor: a first corona shield tape, a stress grading tape, a second corona shield tape having a first overlap length with the stress grading tape and a second greater overlap length with the first corona shield tape, an insulation tape, and a sealing tape.

Abstract: A rotor of a wound rotor motor/generator comprising a plurality of rotor windings including a line rotor coil and a star rotor coil. The rotor coil couples to an L-conductor having an L-shaped profile such that a portion of the L-conductor extends from the line rotor coil toward the star rotor coil. A line connector bar couples the L-conductor to a rotor lead such that the line rotor coil is electrically coupled to the rotor lead. The star rotor coil couples to an L-support having an L-shaped profile such that a portion of the L-support extends from the star rotor coil toward the line rotor coil. An insulator is positioned between the L-conductor and the L-support to electrically insulate the L-support from the L-conductor. Lastly, an insulating rope couples the L-conductor to the L-support.

Abstract: A winding insulation system includes a set of insulated conductors, main wall insulation provided around the conductors, corona shield tape provided around the main wall insulation, stress grading tape provided around the corona shield tape, and sealing tape provided around the stress grading tape. The main wall insulation includes inner, intermediate, and outer sections. The inner section includes polyimide mica paper reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the inner section being provided in half-lap layer(s). The intermediate section includes mica paper reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the intermediate section being provided in half-lap layer(s). The outer section includes mica tape backed with aramid and reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the outer section being provided in half-lap layer(s).

Abstract: An insulation system for an electric machine coil includes the following layers situated in sequence over an insulated conductor: a first corona shield tape, a stress grading tape, a second corona shield tape having a first overlap length with the stress grading tape and a second greater overlap length with the first corona shield tape, an insulation tape, and a sealing tape.

Abstract: A winding insulation system includes a set of insulated conductors, main wall insulation provided around the conductors, corona shield tape provided around the main wall insulation, stress grading tape provided around the corona shield tape, and sealing tape provided around the stress grading tape. The main wall insulation includes inner, intermediate, and outer sections. The inner section includes polyimide mica paper reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the inner section being provided in half-lap layer(s). The intermediate section includes mica paper reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the intermediate section being provided in half-lap layer(s). The outer section includes mica tape backed with aramid and reinforced with any combination of the group consisting of: glass cloth, polyester film, and polyester mat, the outer section being provided in half-lap layer(s).

Abstract: A vacuum pressure impregnation process includes placing a room temperature coil/winding into a pressure vessel with a camera aimed at the coil/winding for inspection, and sealing the pressure vessel to draw a first vacuum level, maintained for a first duration. The coil/winding is flooded with resin and remotely monitored. A second vacuum level is maintained for a second duration while remotely monitoring. A first positive pressure level is applied for a third duration while remotely monitoring, before releasing and drawing a third vacuum level, maintained for a fourth duration while remotely monitoring. A second positive pressure level is applied for a fifth duration while remotely monitoring, before releasing pressure and removing the coil/winding from the pressure vessel.

Abstract: A refurbished rotor of a wound rotor machine. The refurbished rotor includes a plurality of windings assembled to the rotor core, each manufactured from two separate bars: a top coil and a bottom coil. The top coil is positioned in a rotor core slot at a position radially outward of a position of the bottom coil within another rotor core slot. Each top coil and each bottom coil has a flat rectangular cross-section. On a connection end of the rotor where rotor leads are attached, the top coil has a flat end positioned alongside and in alignment with a flat end of the bottom coil of an adjacent one of the plurality of windings. The top coil and the bottom coil have respective flat ends joined to each other on a non-connection end of the rotor opposite the connection end by a joint for establishing electrical continuity.

Abstract: An insulation system of a current-carrying conductor of an electric machine. The insulation system comprises a thermally curable resin including a polymer resin matrix and a nanoparticulate filler. A mica paper or mica tape is impregnated with the thermally curable resin. The thermally curable resin comprises nanoparticulate filler, the total quantity of nanoparticulate filler being at least 0.1 wt % and not more than 0.5 wt %.